How To Lose In One Move

OK, I was already worse when I blundered this afternoon in my round-two game from the Cotswold Congress in Gloucester, but even so …

White has just played 17.h3 in Michael Ashworth (188) - Spanton (171)

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17...Bh5?? 18.Qf5+
The analysis engines Stockfish10 and Komodo9 give best play as 17...d3!? 18.Rxd3 Rxd3 19.exd3 Nd4 20.Bxd4 Bxf3 21.Bxf3 Bxd4, when Black's better coordinated pieces, and White's backward d pawn, give some compensation for the pawn-minus.